Allow specifying HTTP response Content-Type without losing default charset [SPR-13631]

[spring-projects-issues]

Sébastien Deleuze opened SPR-13631 and commented

As discussed in #18178, @RequestMapping "produces" attribute is used for mapping purpose, but also to generate the response content type.

With converters like MappingJackson2HttpMessageConverter when the default MediaType also specify the charset to use, overriding this attribute with "produces" = MediaType.APPLICATION_JSON_VALUE will change response encoding, even that not what most users are expecting (most of them just want to narrow the mapping without affecting the charset).

The goal of this issue is to find if there is a way to easily make it possible to override the mapping related to produces without "reseting" the charset used.

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Affects: 4.2.2

Issue Links:

• StringHttpMessageConverter should use its default charset [SPR-14821] #19387 StringHttpMessageConverter should use its default charset
• Document why "charset=UTF-8" is specified for JSON and not for XML [SPR-14715] #19280 Document why "charset=UTF-8" is specified for JSON and not for XML
• Add MediaType.APPLICATION_JSON_UTF8 and improve documentation [SPR-13600] #18178 Add MediaType.APPLICATION_JSON_UTF8 and improve documentation
• FormHttpMessageConverter should use configured charset (by default UTF-8) for "text-plain" MIME part conversion as well [SPR-14338] #18910 FormHttpMessageConverter should use configured charset (by default UTF-8) for "text-plain" MIME part conversion as well

Referenced from: commits c385427

[spring-projects-issues]

Sébastien Deleuze commented

See also this comment about the potential cause of this issue.

[spring-projects-issues]

Rossen Stoyanchev commented

Just a quick note that this is not only about the produces condition. The Content-Type used in the response may also come from the "requested" content type as determined through a ContentNegotiationStrategy. For example path extension "json" registered against "application/json" will have the same effect.

[spring-projects-issues]

Manuel Jordan commented

Hello

The Content-Type used in the response may also come from the "requested" content type as determined through a ContentNegotiationStrategy. For example path extension "json" registered against "application/json" will have the same effect.

Has sense… perhaps a kind of interceptor should be applied to return always with UTF-8. Of course the user "perhaps" should not be aware about that.

Even more, related with the previous point, in the coming weeks I am going to do my own detailed experiments working with Rest. It in case the RestTemplate sets the Accept to only Json and the content data returns with the weird characters.

My original post #18178 was tested only through a Web Browser. No tested yet through a RestTemplate client.

-Manuel

[spring-projects-issues]

Sébastien Deleuze commented

Rossen Stoyanchev Could you please review the fix I implemented with this commit?

[spring-projects-issues]

Sébastien Deleuze commented

I have updated the commit with Rossen feedback about ObjectToStringHttpMessageConverter and StringHttpMessageConverter, and will merge it shortly in master.